BUG=266
TEST=unittest for color table passes and is faster
R=thorcarpenter@google.com

Review URL: https://webrtc-codereview.appspot.com/2181009

git-svn-id: http://libyuv.googlecode.com/svn/trunk@789 16f28f9a-4ce2-e073-06de-1de4eb20be90